For cancer survivors, the battle does not stop with the treatment. The side effects of cancer therapy and the fear of recurrence often haunt them for years.

A new study conducted on breast cancer survivors reveals the possibility of one such side effect of cancer treatment. A Moffitt Cancer Center researcher, along with researchers from the National Institute of Health, found that women who have been treated for breast cancer experience faster aging.

Breast cancer is one of the most common cancer diagnosed in women in the U.S. The number of deaths associated with the disease is steadily declining as early detection helps in effective treatment and recovery.

According to the latest study, the most pronounced effect on aging was in people who received radiation therapy, while people who underwent surgery as part of the treatment showed no association. Researchers believe that developing cancer is not the cause of the aging effect but the treatment associated with it.

"Breast cancer survivors have higher rates of various age-related diseases, such as cardiovascular disease, and experience faster physical and cognitive decline than women without a history of breast cancer. In this study, we wanted to explore the biology behind this and examine whether certain cancer therapies had a greater long-term impact on survivors," study lead Jacob Kresovich, assistant member of the Cancer Epidemiology Department at Moffitt, said in a news release.

The researchers used data from a study conducted by the National Institutes of Environmental Health Sciences, which evaluated environmental and biological factors that contribute to breast cancer risk and survival. From among 50,000 participants, researchers studied 417 women who provided blood samples at two time points about eight years apart. They were treated for breast cancer between their first and second blood draws.

The team then evaluated the changes in the participant's biological aging between the time points. It was measured at the molecular level using DNA methylation, a naturally occurring DNA modification across the lifespan.

Women diagnosed with cancer aged faster compared to those who did not have cancer. Researchers then examined how the treatments such as chemotherapy, radiation therapy and endocrine therapy affected aging.

"Of the three treatment classes we looked at, radiation therapy had the strongest associations with the biological age measures assessed in the study. The increases can be detected years after treatment," said Jack Taylor, a senior author of the paper.

However, the team does not undermine the effectiveness of radiation therapy as a breast cancer treatment and cautions patients not to stop radiation treatment.

"Radiation is a valuable treatment option for breast cancer, and we don't yet know why it was most strongly associated with biological age," said Dale Sandler, chief of the Epidemiology Branch at the National Institute of Environmental Health Sciences and a co-author of the paper.